Heating and radiating unit for electric heaters



H. J. ORR

May 12, 1970 HEATING AND RADIATING UNIT FOR ELECTRIC HEATERS Filed Sept. 7, 1967 2 SheetsSheet 1 ATTORNEY5 May 12, 1970 Filed Sept. 7. 1967 2 F I G 6 STAMPING A PPARATUS H J. ORR 3,510,940

HEATING AND RADIATING UNIT FOR ELECTRIC HEATERS Sheets-Sheet 2 EDGE A P P A R AT US FIN ELEMENT FORMING APPARATUS FIN STAMPING APPARATUS mvEN'roR f/Amrr J ORR 33 2M MM ATTORNEYS Un t S t s Farm ,0

U.S. Cl. 29611 8 Claims ABSTRACT OF THE DISCLOSURE An electric heating element for baseboard heaters or the like wherein strips of supporting material, insulating strips and a heater element strip are fed to a forming and gathering apparatus and formed into a heating unit. The supporting material preferably has fins stamped thereon.

This invention relates to convection heaters and more particularly to electric heaters of the Wall or baseboard t pe.

Heaters of this type are well known in the heating art but, in general, have radiating fins so attached to the sheath member as to produce noise and poor heat transfer.

One of the'objects of the present invention is to provide a heating unit for a baseboard or wall type of heater which is simple and inexpensive in its method of manufacture.

A further object of the invention is to provide a heating unit for wall or baseboard type of electric heaters which is made from strip material and in which the radiating fins areintegrally attached to the sheath containing the heating element.

A further object is to provide'a heating unit in which the heating element, sheath and radiating fins comprise one unitary, composite, strip-like member easily installed and economically manufactured.

In one aspect of the invention, the wall or baseboard heater comprises elongated housing members enclosing a wireway, a heat deflecting baflle, and a heating and radiating member suspended by hangers or the like. The heating and radiating member comprises a composite unitary strip composed of two strips or sheets of aluminum or suitable material having fins formed therefrom and having a heating element with mica or similar insulating material on each side thereof contained within the aluminum sheets. The entire composite strip is preferably formed in a simple, automatic operation in which strips of thin metal such as aluminum, strips of thin insulating material such as mica, and a preformed heating element are fed to forming and edge-bending dies to provide the composite strip. The invention also can be practiced without fins.

As a second aspect of the invention, the composite heater and fin strip may comprise a single strand of preformed heater resistance wire or material tudinally of the strip, or it may comprise a multiple strand of resistance wire extending through the upper portion of the strip and bent backwardly to extend through the lower portion of the strip. The strip may or may not be sealed against entrance of moisture at each end thereof.

As a third aspect of the invention, a third strip of aluminum or suitable metallic material may be interposed between one of the stamped metallic strips and its adjacent insulating strip, or such a strip may be positioned between each of the outer stamped sheets and its adjacent insulating strip.

extending longi-- 3,510,940 Patented May 12, 1970 drawings which illustrate exemplary embodiments of the invention.

In the drawings:

FIG. 1 schematically illustrates the type of heater in which the unitary heating and fin assembly of the invention may be utilized;

FIG. 2 is a perspective view of the unitary and composite heater and fin unit;

FIG. 3 is an elevational view of the unit of FIG. 2;

FIG. 4 is a cross sectional view taken on the line 44 of FIG. 3;

FIG. 5 is a view similar to FIG. 3 but illustrating a modified form of the heating element; and

FIG. 6 illustrates the method for forming the composite or unitary heating and fin strip of FIG. 2.

Referring to the drawings and more particularly to FIG. 1, there is shown a housing 10 comprising a back plate 11 adapted to attach the baseboard to a wall, a wireway 12, a deflector plate 13, a grille or screen guard 14, a front member 15, and a heating and radiating unit or member 16. Electric wiring for the heating element is adapted to extend through the wireway 12 and connect with the leads 17 (FIG. 2, 3 and 5) of the heating element. Suitable thermostatic and fail-safe control elements (not shown) may also be incorporated in the housing 10 in a well known manner As more particularly shown in FIGS. 2 to 4, the heating and radiating unit or member 16 comprises a unitary composite strip formed from two sheets 18 and 19 of aluminum or the like encompassing a pair of strips or sheets 20 of mica or similar insulating material overlying a preformed heating element 21. The stripes 18 and 19 are stamped or pressed to form the fins 22, the

fins of one strip extending in one direction and those of the other in the opposite direction, as illstrated in FIGS. 2 and 4. If desired, a third sheet or strip of aluminum 19A (dashed lines, FIG. 6) may extend between the sheet 19 and its associated mica strip 20 to protect the insulating strip 20 at the openings 23 from which the fins 22 are punched. The aluminum sheet or strip 18 is wider than the strip 19 to provide upper and lower portions adapted to be folded or crimped as shown at 24 in FIGS. 2 to 4 to clamp or secure the heating and radiating unit 16 into one unitary composite strip or structure. The heating element 21 preferably comprises a wire like resistance preformed into a relatively fiat, open loop or cycle-like formation as shown in FIGS. 3, 4 and 5.

In FIGS. 2 to 4, the open loop or cycle-like resistance wire or heating element 21 extends through the upper portion of the heating unit 16 and then bends backwardly to extend through the lower portion of the heating unit. Depending upon the heating wattage desired, however, the heating element or resistance wire 21 may comprise a single or multiple strand extending continuously through the unit 16 and having terminals at each end thereof as illustrated in FIG. 5. The ends of the unitary heating and radiating unit 16 may also, if desired, be sealed against the entrance of moisture by a suitable silicon or ceramic compound. As is also known in the wall or baseboard heating art, there is a tendency for heat to concentrate in the central portion of the heating unit. To avoid this, the invention also contemplates the spreading of the convolutions of the open loop or cycle-like heating element 21 to provide a greater density of heat at the ends of the unit 16.

In FIG. 6 there is illustrated a method for the automatic, simple and economical forming of the composite and unitary strip or heating unit 16. Referring to FIG.

6, sheets or strips 18 and 19 in roll forms 30 and 31 are fed to fin stamping apparatus or dies 32 wherein the fins 22 are formed from the relatively thin sheets of metallic or suitable material. The formed strips are then fed to a composite strip forming or gathering apparatus or element 33. Also fed to the gathering apparatus 33 from rolls 34 or the like are two sheets or strips of mica or insulating material and a strip of electrical resistance or heating wire 21 supplied from a coil 35 and preformed by apparatus such as dies 36 into a substantiallyflat open loop or cycle-like formation as shown in FIGS. 3 and 5. The outer portions of the Wider strip 18 are then folded or crimped around the strips 19, 20 and 21 by a suitable forming apparatus or dies 37 to provide a unitary composite heating and radiating strip or unit assembly 16. Thereafter the composite strip is cut into predetermined lengths and the cut ends may be sealed against entrance of moisture by a suitable silicon compound or the like. Also, the terminal leads 17 are attached. If a third metallic strip is desired between one of the finned strips and an insulating strip, as above described, it would be fed to the gathering apparatus 33 from a roll of the strip material (not shown).

The heating element may be of resistance wire, graphite deposit on insulating material, or a printed circuit type element. Also, the fins may be omitted and the element sheath may be metallic or insulating material.

' What is claimed is:

1. The method for forming a unitary heating unit for baseboard or similar electric heaters which comprises feeding metallic supporting strips to a fin stamping apparatus to provide radiating fin-like members thereon and thence to a gathering and composite strip forming apparatus, stimultaneously feeding two stris of insulating material and an electric heating element to said gathering and forming apparatus, said strips of insulating material being contained between said strips of supporting material and said heating element being contained between said strips of insulating material, and bonding one of said sheets of supporting strip material to the other of said supporting sheets to provide a unitary heating unit comprising a composite strip having said heating element and said insulating strips contained therein.

2. The method as defined in claim 1 in which said strip-like sheets of supporting material, said strips of insulating material, and said heating element are supplied from rolls of the respective materials.

3. The method as defined in claim 1 in which said heating element is preformed into a substantially fiat open loop cycle-like formation.

4. The method defined in claim 3 wherein said open loop cycle-like formations of said heater element are closer spaced toward the ends of the heater unit to distribute heat dissipation more evenly along the length of the unit. t

5. The method as defined in claim 3 in which said preformed heating element extends continuously through the heater unit.

'6. The method as defined in claim 3 in which said preformed heating element is bent backwardly to extend through upper and lower portions of the heater unit.

7. The method as defined in claim 1 wherein a third thin strip of metallic material is fed to said gathering and strip forming apparatus to be positioned between one of said stamped metallic strip-like sheets and one of said insulating strips in the assembled composite strip.

.18. The method-as defined in claim 1 wherein the composite strip comprising the assembled heating unit is cut into strips of predetermined length and a sealing compound is applied to the ends of said lengths to guard against entrance of moisture.

References Cited UNITED STATES PATENTS WILLIAM I. BROOKS, Primary Examiner US. Cl. X.R. 29--613; 219-544 

